This invention relates to a machine for forming large cylindrical bales of crop material, commonly called round bales, and more particularly to apparatus for wrapping the completed bale with a binding material in a coiled fashion between the bale's opposing ends. The apparatus, once it is triggered, functions automatically to wrap the binding material about the bale of crop material as the bale is rotated about a horizontal axis prior to the bale's being discharged from the bale forming machine. The apparatus will also effect the automatic cutting of the binding material at the end of the wrapping cycle.
Historically, it has been the custom to harvest forage crops by mowing the crops, letting them dry in the field, forming the dried crop material into windrows and passing a hay-baling machine over and along these windrows to form the crop material into rectangular bales. Recent practice has shown that the formation of crop materials into large compact rolls, rather than rectangular bales as formerly done, permitted the crop material to be deposited in roll form and left in fields for extended periods of time since the rolled material tends to provide a self-shedding protective covering from inclement weather. The ability to leave these rolled bales in fields thus obviated the additional steps of gathering the rectangular bales and transporting them to a storage area protected from the elements.
Several methods for forming compact rolls of crop material have evolved through the years. The original use of compact rolls of crop material can be traced back 30 or 40 years to the small cylindrical bale of hay or other fibrous material produced by the type of machine illustrated in U.S. Pat. No. 2,336,491, dated Dec. 14, 1943. This method produced compact rolls of crop material, but suffered from the principal disadvantage of having those rolls being of such small diameter that the spoilage due to weathering around the periphery of the roll was excessive in comparison to the overall diameter of the roll when stored in the field. In another method, a machine rolled a swath or windrow of crop material along the ground until a roll of desired size was obtained. An example of a machine utilizing this principle is shown in prior U.S. Pat. No. 3,110,145 dated Nov. 12, 1963. The principal difficulty encountered in using this technique resulted from the fact that a certain amount of the crop material remained upon the ground without being included in the crop roll and dirt, clods of earth, stones and the like were picked up by the roll and included therein. These characteristics proved to be undesirable under many circumstances, although the formed roll of crop material was large enough to make it economically feasible to store outside in a field with no cover without encountering excessive weathering losses. A later and more successful method of forming crop rolls utilized machines which picked up a swath or windrow of crop material from the field and deposited it onto a lower conveyor. The conveyor transported the material to a roll forming region where an upper apron or flight of belts, usually positioned above and adjacent the conveyor, moved in a suitable direction to rotate the crop material and form a large compact cylindrical bale. Variations of the type machines utilizing this principle are illustrated in U.S. Pat. No. 3,859,909 to Mast, dated Jan. 14, 1975 and U.S. Pat. No. 3,722,197 dated Mar. 27, 1973.
All of the above cited methods of forming compact rolls of crop material of varying sizes utilized in some form crop material binding means. The binding material commonly took the form of twine and the binding means, accordingly, became known as twine wrapping means or apparatus. The apparatus was used in a twine wrapping cycle that included the steps of feeding the twine, wrapping the completed roll or bale and severing the twine prior to ejecting the roll or bale from the machine. Automatic twine wrapping apparatus which serially undertook the aforementioned three steps without any operator involvement, hydraulically or electrically powered apparatus requiring manual activation, and completely manually operated twine wrapping apparatus have been used in the art on the varying machines employing the different methods of forming cylindrical rolls of crop material. Operators and manufacturers of the earliest roll forming machines, generally of the type described in the above-cited U.S. Pat. No. 2,336,491, quickly realized the advantages of employing automatic twine wrapping apparatus to bind the completed crop roll or bale to ensure that it maintained its cylindrical form after ejection from the bale forming machine. Twine wrapping apparatus of the type shown and described in U.S. Pat. No. 2,468,641, dated Apr. 26, 1949, employed automatic twine wrapping apparatus to wrap the completed cylindrical bale with binding material without having the operator leave his towing vehicle or manually power the twine wrapping apparatus.
The current increasing popularity of large crop roll forming machines has seen their use broaden from merely rolling wintering forage for livestock to rolling high protein crops. Therefore, these machines have been the focal point of many ideas for developing an automatic twine wrapping apparatus that could be utilized on the different bale forming machines that produce large, cylindrical compact bales varying in weight from 850 to 1500 pounds or more. The twine apparatus employed in the earlier roll forming machines was not satisfactory for adaptation to these new, larger machines.
Previous crop roll forming machines that produced the large cylindrical crop rolls employed either manually powered twine wrapping apparatus or manually controlled twine wrapping apparatus. Because these larger bale forming machines must be pulled by tractors frequently requiring substantial horsepower and size, the seats for the operators of these tractors were standardly enclosed within a cab or were sufficiently remote from the bale forming machine so that it was difficult, at best, for the operator to utilize manually powered twine wrapping apparatus. Even twine wrapping apparatus that was merely manually controlled required the operator to look back over his shoulder and observe the twine wrapping cycle taking place in the bale forming machine. Regardless of the type of twine wrapping apparatus employed, the requirement for the tractor operator to look over his shoulder caused the operator to be excessively fatigued at the end of a typical day of 8 or 10 hours of operating a roll forming machine.
Additionally, the older type bale forming machines that produced the comparatively small cylindrical bale and utilized automatic twine wrapping apparatus suffered from the disadvantage of not being able to adjust the timing of the activation of the twine wrapping apparatus so as to be able to form bales of varying desired size. With the advent of large bale forming machines in the agricultural industry it has become necessary to eject a less than full size bale from the bale forming machine either because of the exhaustion of the supply of windrowed crop material in a field or because of the occasional mechanical malfunctioning of the bale forming machine. Additionally, the automatic twine wrapping apparatus employed on the older type bale forming machines were activated through relatively complex linkage and clutch arrangements.
The foregoing problems are solved in the design of the apparatus comprising the present invention by permitting the automatic twine wrapping apparatus to be actuated by either one of two mechanisms when a desired bale size is obtained.